Niveums silver leaf, nutrient deficiency or?

[IvoPhal]

I have 2 pots 12 cm with 3 niveums. They are potted in bark, perlite and quarts sand. I used in thei culture since September kelpak and akerne feet, calamag, oyster shells sand and some seaweed. All are derived from 1 pot when I bought it.
The 1 one is in good shape planted alone(see pics) the other one is in bud with 2 yellow leaves ( that’s my concern) and the other one is not growing.
Why they react so differently? They are treated the same way, light, temp at the windowsill? Is there some nutrient deficiency or I have to see roots ….

 

[big923cattleya]

Are those mealybugs down in the growth with the bud? It sure looks like it but from your images I can not be sure.
This group of orchids, the Brachypetalums are fairly slow growers. They live in the leaf litter one top of limestone outcroppings. They never really like to dry out and mine do not seem to enjoy being too wet either. Niveum, concolor, godefroyae, bellatulum, leucochilum, etc. all feature dark green leaves with silver markings or tessellations.
They are small plants, I would be careful about applying too much fertilizer. I my experience under lights, they prefer subdued light and both concolor and bellatulum are the easiest for me to grow.

 

[IvoPhal]

No, it’s not mealy bugs, oysters shell sand but a messy application
Actually the question is that one plant potted in 2 pots, the same media , fertiliser msu/akerne 100 N ppm weekly is growing differently.
1. Is growing with strong leaves
2. Is blooming but the the leaves are yellowing
3. Plant it’s not growing